Heat sensitive device



E S Y E K H A l-lEAT SENSITIVE DEVICE 2 Sheets-Sheet 1 Filed Sept. 27, 1947 INVENTOR. ALLEN H. KEYSER ATTORNEY m NIL] may 30 i950 A. kvslg 2,509,825

I mi* SENSITIVE DEVICE Filed Sept. 27, 1947 2 Sheets-Sheet 2 ALLEN H. KEYSER By' I di,

ATTORNEY.

Patented May 3 0, 1950 j y l A UNITI-:o Isnlii'rlsys1 PATENT orrica HEAT SENSITIVE nnvrcn Allen H. Keyser, Worcester, Pa., assignor, by mesne assignments, to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application September 27, 1947, Serial No. 776,572

3 Claims. (Cl. 13G- 4) This invention relates to heat measurement Fig. 6 with the outer layers indicated by broken and more particularly to a plurality of thermolines.

couples connected in series to form a ther- One preferred embodiment of thlsinvention,

mopile. f selected from Aamong others for illustration in It is an object of this invention to provide a 5 the drawing andfdescription in the specification,

heat sensitive element suitable for measuring isas follows.

animal body temperature by insertion into a Six wires, II, I2, I3, I4, I5, I6, each about 'I natural cavity of, or into an incision in the body iive feet in length are provided. Three of these of an animal, such as a guinea pig, used for labwires are of one metal, such as copper, and the oratory experiments. loother three of another metallic composition, such It is a further object of this invention to proas constantan. While copper and constantan vide a'thermopile in which each thermocouple are the preferred materials for these wires, any is insulated from the other therrnocouples by a pair of dissimiliar metals or alloys may be used sleeve of loosely woven glass fabric, a tube of provided they give an appreciable voltage when loosely woven glass fabric supporting, all the 15 joined together at one end and heated, while the sleeves, and a lump orsolidbody of plastic imother end remains relatively cool. ATheodd and pregnating and embodying the thermocouples, even numbered wires are joined together at one the glass sleeves and the glass tube and comend by having the softer wire coiled about the pletely containing them. harder and soldered, welded and otherwise united The various 'features of novelty which char- 20 into a helically shaped thermocou'ple, of which acterize this invention are pointed out with parone is seen at I'I in Fig. 1. ticularity in the claimsv annexed to and forming Each of the wires has on it, except at thebare a part of this specication. For a better underend at which it is joined to another wire, a1ayer standing of the invention, however, its advanof threads of insulation I8, such as cotton thread.

tages and Specific Objects Obtained with its use, 25 These insulating layers may, if desired, be of difreference should be had to the accompanying ferent colors so as to identfy the individual wires.

drawings and descriptive matter in which is illus- A relative small and short sleeve of loosely woven trated and described a preferred embodiment of glass fabric is placed around each thermocouthe invention. ple and the adjoining layers of insulation I8.

Of the drawings, of which Figs. 1 to 4 are on 30 These sleeves are marked I9, 20 and 2I on the a greatly enlarged scale-Fig. 1 is a view of a drawings. The sleeves I9, 20 and 2| extend for longitudinal cross section with parts broken away substantially the entire length of the thermomtransversely to reduce the overall length of the eter rearwardly or to the left as seen in Fig. l gure. The left hand side of the gure is taken from the thermocouples Il. At their rear or opon a substantially diametric line I-I of Fig. 2. 3 posite ends from the thermocouples Il, the ends The central part of the ligure is taken on a curved of the sleeves adjoin the end of a layer of rubline IA-IA of Fig. 3 just above the glass sleeves, ber-like sheathing or insulation 22 which surthe outer layers being removed for clarity. The rounds the insulated wires and forms them into right hand part of the figure is taken on a line a cable. The wires and their insulating cover- IB-IB of Fig. 4 just outside one of the thermo- 40 ings may be coiled or wound into a helical form couples. The broken away sections are viewed within the sheathing 22.

in the direction of the arrows applied to the above A ring or ferrule 23 of metal is placed over the mentioned section lines. end of the sheathing 22. One or both ends of the Fig. 2 is a transverse cross section on line 2-2 ferrule 23 may be spun over or clinched, as inof Fig. 1 as viewed in the direction of the ar- 45 `dicated at 24, to retain the ferrule 23 on the rows. 'sheathing 22 and to seal the cable against the Fig. 3 is a transverse cross section on line 3 3 entrance of air or moisture. A relatively large of Fig. l as viewed in the direction of the arand long tube 25 of loosely woven glass fabric is rows. placed over the ferrule 23.and in contact with a Fig. 4 is a transverse cross section on line 4--4 50 portion of the outer surfaces of the sleeves I9, of Fig. l as viewed in the direction of the arrows. 20 and 2i. Fig. 5 is a longitudinal elevationl on full scale. A solid block or body of plastic 26, such as an Fig. 6 is a partial longitudinal cross section unsaturated polyester resin type, is formed on the substantially of the same parts shown in the left surfaces of the thermocouples I'I, the sleeves I9, hand side of Fig. 1 and with the middle part 5 20 and 2|, the ferrule 23, and the tube 25. This broken away substantially in the line E--B of body of plastic impregnates any openings in the Fig. 3 as viewed in the direction of the arrows. sleeves and in the tube and completely imbeds Fig. 7 is a. phantom or partial perspective view and surrounds the other elements. The outer in transverse cross section as viewed in the disurface of the plastic body 26 is smoothed oi rection of the arrows applied to the line Iv-'I of 60 so that there is provided -a stiif, light, smooth and otherwise attractive and' desirable protecting -body forl the thermopile and the protecting glass sleeves surrounding the individual thermocouples and the glass tube.

The process of manufacturing this thermometer is as follows: The ends of the wires iI-IS are dipped in clear varnish and dried in air. The layer of insulating fabric i8 is then removed from each of the Wires Ii-iG for about onehalf inch from one end. The ends of the individual wires I I-I.8. are then cleaned to a bright metallic surface, twisted ina. helical coll and welded together. The individual thermocouples thus formed are insulated with one dip coat of suitable insulation and allowed to dry in'air for one half hour. The ferrule 23 is then slipped over and iirmly fastened on the end o1' the rubber' insulating coating 22. The smaller, shorter sleeves I9, 20, and 2i are .next slipped over each of the thermocouples i1 and the wires with their insulating coating i8 which form the leads to the thermocouples. The reinforcing tube of loosely knit glass fabric is then placed longitudinally over the thermocouples and the smaller shorter glass sleeves surrounding them. The end of the glass nbre tube 25 overlies at least a portion of the ferrule 23. The parts thus assembled are placed in a suitable mold, such as a small glass tube. One end of this glass tube is dipped beneath the surface of fluid plastic. such as unsaturated polyester resin type. A vacuum is applied to the upper or opposite end of the solid heat. When the plastic body is sufficiently hard v to withstand handling, it is removed from the mold or glass tube and any rough edges or projecting portions of the outer surface of the plastic body 26 are removed. There is `thus formed a thermometer including a thermopile which can be used in a cavity or incision in the body of an animal, without unnecessary irritation. In use, the thermometer .remains within the Ibody of the animal for a period-of one half hour/or more. f f

While in accordance with the provisions of the statutes, I have illustrated and described the best forms of the invention now known to me, it will be apparent to those skilled in the art that vchanges may be made in the form of the apparatus disclosed without departing from the spirit of the invention as set forth in the appended claims, and that in some cases certain features of the invention may sometimes be used to advantage without a corresponding use of other features.'

VHaving now described my invention what I claim as new and desire to secure with Letters Patent is as follows: v

1. A temperature-measuring device for insertion into the body of an animal, said device including a solid mass of set unsaturated polyester resin type plastic of low heat conductivity having a smooth outer surface, a stifening layer formed of a tube of loosely interlaced threads of glass fibre embedded in the mass of plastic, a metallic ring embedded in the mass `of plastic beneath a portion of the tube of glass bre, a tubular layer of exible insulating material pro- Jecting into the mass of. plastic and closely encircled by the metallic ring. a plurality of tubular insulating coverings twisted together within the tubular coating, a plurality of wires of at least two diilerent metallic materials each enclosed within one of said coverings, thermocouples formed of the ends of pairs of said wires of different material intimately joined together to form hot junctions, and a plurality of sleeves of loosely interlaced threads of glass fibre, said sleeves being of smaller diameter and shorter length thansaid tube of glass nbre and each embedded in the mass of plastic and encircling one of said thermocouples and a portion of the two tubular insulating coverings leading to the thermocouple so that said sleeves insulate the thermocouples and the adjacent portions of the tubular insulating coverings for the wires forming each thermocouple from the other thermocouples and pairs of wires.

2. A temperature sensing device including, a

cable formed` of a number of wires each having a layer of insulation on it and coiled about one another within a flexible insulating sheath, a ferrule circumscribing oneend of each sheath, the ends of a pair of said wires of different metallic materials beingv united together to form a heat-responsive source of small voltage, a thickness of loosely knit glass textile girdling the ends of the Wires, and a cohesive lump of permanently hardened plastic enveloping the ends of the wires and oi their coatings and the sheath, the ferrule and the textile.

3. A temperature sensing device made up of a plurality of `wires of a metallic material and an equal number of wires of a different metallic material joined together in pairs at one end to.

constitute thermocouples; a relatively short sleeve of glass cloth encircling each thermocouple; a relatively long sleeve of glass cloth encircling all of the thermocouples; a layer of threads encircling each wire except at the end formed into a thermocouple; a layer of rubber encircling the wires and the layers of threads and forming them into a cable; a ferrule encircling the end of the rubber/layer; and a solid mass or body of set unsaturated polyester resin type plastic surrounding the thermocouples and the glass sleeves and having a smooth outer surface.

ALLEN H. KEYSER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,289,116 Chubb Dec. 31, 1918 2,278,744 Sparrow et al. Apr. 7, 1942 2,378,804 Sparrow et al June 19, 1945 2,414,525 Hill et at. Jan. 21, 1947 OTHER REFERENCES Taylor, G. F.: J. Ind. & Eng. Chem., vol. 12, Aug. 1920. page 797.

McConnell et al.: Trans. Am. Soc. Heat. 8: Ventil. Engrs., vol. 28 (1922), page 215.

Trimble, H. M.: J. Ind. & Eng. Chem. (Anal. Ed), v01. 12 (1940), p. 52. Copy in Div. 59.

Hess et al.: Welding Journal, November 1943, page 560-s. 

